Phase-changed heat dissipating device and method for manufacturing it

ABSTRACT

A phase-changed heat dissipating device includes a hollow tube and a driving member connected to the tube. The tube has a vaporizing portion and a condensing portion and contains working fluid therein. The driving member includes a plurality of shrinkable chambers serially connected together to drive the working fluid to flow.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a phase-changed heat dissipating device and method for manufacturing it, and more particularly to a phase-changed heat dissipating device with an excellent circulation of working liquid to improve heat dissipation efficiency of the device and a method for manufacturing it.

2. Description of Related Art

As we know, a heat pipe is a conducting device which realizes conduction with working liquid therein, taking advantage of high conduction and good isothermal character. Therefore, it is widely used.

For these years, with the rapid development of electric technology, heat generated by electrical component increases highly. Therefore, phase-changed heat dissipating devices having good heat transfer performance have been widely used.

As shown in FIG. 5, commonly, a heat pipe comprises a sealed container 11 with internal walls coated with a capillary wick structure 4 that is filled with working fluid 13. The heat dissipating device 10 is commonly filled up the working liquid 13 after pressing the heat pipe to be vacuum. Then the container 11 is sealed when the wick structure 4 is fully filled with the working liquid 13. The heat pipe comprises a vaporizing portion 10 a, an adiabatic portion and a condensing portion 10 b. When the heat pipe absorbs heat at the vaporizing portion 10 a thereof, working liquid 13 is vaporized to vapor, and a pressure gradient is formed in the heat pipe. This pressure gradient forces the vapor to flow from the vaporizing portion 10 a to the condensing portion 10 b where the vapor condenses and gives out its latent heat. The working fluid 13 is then returned back to the vaporizing portion 10 a of the heat pipe via capillary forces developed in the wick structure 4.

A main function of the wick structure 4 in above circulation is to stimulate the return of the working liquid 13 to the vaporizing portion 10 a. Commonly, sintered power and screen mesh are applied into a pipe to act as a wick structure. Another type of wick structure pipe is a grooved tube. However, the grooved tube is in high cost of the die and machine. It is difficult for the screen mesh to realize complete autoimmunization; thus, manpower cost is much high. A problem for the sintered power is that it needs a costly vacuum sinter furnace.

Therefore, it is desired to design a heat pipe which can improve heat dissipation efficiency and reduce manufacturing cost thereof.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a phase-changed heat dissipating device which has improved heat dissipation efficiency.

Another object of the present invention is to provide a phase-changed heat dissipating device having low manufacturing cost.

Another object of the present invention is to provide a method for manufacturing above-mentioned heat dissipating device.

In order to achieve the object set out above, a phase-changed heat dissipating device in accordance with the present invention comprises a hollow tube and a driving member. The tube comprises a vaporizing portion and a condensing portion and is contained working fluid therein. The driving member comprises a plurality of chambers serially connected together. The driving member is connected to the tube to form a loop for circulation of the working fluid and the chambers are shrinkable to discharge the working fluid therein.

Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 are plan views of a phase-changed heat dissipating device in accordance with a preferred embodiment of the present invention; and

FIG. 5 is a cross-sectional view of a conventional heat dissipation device.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made to the drawing figures to describe the present invention in detail.

FIGS. 1-4 show a phase-changed heat dissipating device in accordance with the preferred embodiment of the present invention, for removing heat from computer electronic devices such as CPUs (not shown). The phase-changed heat dissipating device comprises a hollow tube 2, working fluid 3 filled in the tube 2 and a driving member 4.

The tube 2 is made of copper or other metal materials in accordance with different needs, such as aluminum, steel, stainless steel, iron, nickel, titanium alloy etc. A radial cross section of the tube 2 is round in the preferred embodiment of the present invention, but it can be others, such as ellipse, square, rectangle or triangle. The tube 2 comprises a vaporizing portion 2 a and a condensing portion 2 b. Two conduits 9 are attached to opposite ends of the tube 2 by means of O-shaped rings. The conduits 9 are made of metal or rubber.

The driving member 4 is connected to the tube 2 via the conduits 9, and drives working fluid 3 from the condensing portion 2 b to the vaporizing portion 2 a through the conduits 9. The driving member 4 comprises four different sizes of chambers 5, 6, 7 and 8, which are made of piezoelectricity material. The piezoelectricity material is a compound of lead, zirconium, acid and titanium. The piezoelectricity material is to produce driving force by physical deformation thereof, under electrical signals. The four chambers are all column-shaped, serially connected together via O-shaped rings made of rubber. The rings are used to compart the chambers 5, 6, 7, 8, and prevent the working fluid 3 from leaking. Two ends of the conduits 9 are also joined to the chambers 5, 8 by O-shaped rings. Each of the chambers 5, 6, 7, 8, is controlled by an AC electrical signal 20. Aphasic interval of the adjacent AC electrical signals 20 is 90 degrees every interval time T. The corresponding chambers have the same phasic interval according to the signals imposed thereon at the same time. The time T is the one during which the working fluid 3 flows from a chamber to a next one. When inputting the AC electrical signals 20 on the chambers 5, 6, 7, 8, the volume of each chamber is periodically changed with physical deformation. Then the chambers 5, 6, 7, 8, drive the working fluid 3 therein to a next one.

The working fluid 3 is liquid, such as water, ammonia, carbinol and heptane. Particles of conduct materials such as copper power are added to the working fluid 3 to improve the conduction capability of the phase-changed heat dissipating device. The working fluid 3 is chosen to be water in accordance with the preferred embodiment of the present invention.

As shown in FIG. 1, the working fluid 3 of the vaporizing portion 2 a is vaporized into vapor when the vaporizing portion 2 a of the tube 2 absorbs heat. The vapor flows to the condensing portion 2 b of the tube 2 with the pressure gradient forces, condenses into the working fluid 3 and gives out its latent heat of vaporization. The working fluid 3 flows into chamber 8 via the conduits 9. The chamber 8 is shrunk in light of the AC electrical signal 20 imposed thereon at a time T. The chambers 5, 6, 7 are also correspondingly changed according to the AC electrical signal 20 imposed thereon. After the time T, the chambers 5, 6, 7, 8 enter a next working state, as shown in FIG. 2.

As shown in FIG. 2, after the time T, the working fluid 3 has been forced by the chamber 8 to flow into the chamber 7 next to the chamber 8. The chamber 7 is shrunk in light of the AC electrical signal 20 imposed thereon at a time 2T. The chambers 5, 6, 8 are also correspondingly changed according to the AC electrical signal 20 imposed thereon. After the time 2T, all of the chambers 5, 6, 7, 8 enter a next working state, as shown in FIG. 3.

As shown in FIG. 3, after the time 2T, the working fluid 3 has been forced by the chamber 7 to flow into the chamber 6 next to the chamber 7. The chamber 6 is shrunk in light of the AC electrical signal 20 imposed thereon at a time 3T. The chambers 5, 7, 8 are also correspondingly changed according to the AC electrical signal 20 imposed thereon. After the time 3T, all of the chambers 5, 6, 7, 8 enter a next working state, as shown in FIG. 4.

As shown in FIG. 4, after the time 3T, the working fluid 3 has been forced by the chamber 6 to flow into the chamber 5 next to the chamber 6. The chamber 5 is shrunk in light of the AC electrical signal 20 imposed thereon at a time 4T. The chambers 6, 7, 8 are also correspondingly changed according to the AC electrical signal 20 imposed thereon. After the time 4T, all of the chambers 5, 6, 7, 8 enter a next working state, as shown in FIG. 1.

As shown in FIG. 1, after the time 4T, as the chamber 5 becomes smaller than that at the time 4T. The working fluid 3 is forced to flow to the vaporizing portion 2 a of the tube 2 on account of the deflation of the chamber 5. Then the working fluid 3 arriving at the vaporizing portion 2 a begins a next new circulation.

In manufacturing the heat dissipating device, the tube 2 is filled with the working fluid 3 therein. Two conduits 9 are respectively attached to opposite ends of the tube 2 by O-shaped rings. A driving member 4 connects the conduits 9, and is communicated with the tube 2 via the conduits 9 to form a hermetical circulation. The AC Electrical signals 20 are provided on the driving member 4. The driving member 4 is deformed and thus drives the working fluid 3 to flow.

Since the working fluid 3 is forced by an additional driving member 4, the flow of the working fluid 3 is enhanced, though without a wick structure employed in the phase-changed heat dissipating device. This also saves cost for wick structure so that whole manufacturing cost of the heat dissipating device is decreased in comparison with conventional heat pipes.

It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present example and embodiment is to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein 

1. A phase-changed heat dissipating device for dissipating heat from a heat-generating component, comprising: a hollow tube comprising a vaporizing portion and a condensing portion; working fluid; and a driving member comprising a plurality of chambers serially connected together; wherein the driving member is connected to the tube to form a loop for circulation of the working fluid and the chambers are shrinkable to discharge the working fluid therein.
 2. The phase-changed heat dissipating device of claim 1, wherein the chambers are made of piezoelectricity material.
 3. The phase-changed heat dissipating device of claim 1, wherein the driving member comprises four chambers.
 4. The phase-changed heat dissipating device of claim 3, wherein each of said chambers is controlled by an electrical signal.
 5. The phase-changed heat dissipating device of claim 4, each of said chambers is shrunk in light of an AC electrical signal imposed thereon.
 6. The phase-changed heat dissipating device of claim 4, wherein a phasic interval of the electrical signal imposed on two adjacent chambers is 90 degrees.
 7. The phase-changed heat dissipating device of claim 1, further comprising two conduits connecting the driving member to the tube.
 8. A method for manufacturing the phase-changed heat dissipating device comprising steps of: offering a hollow tube having working fluid contained therein and a driving member; offering conduits connecting the driving member to the tube to form a loop; and providing electrical signals on the driving member to allow the driving member to drive the working fluid to circulate in the loop.
 9. The method as claimed in claim 8, wherein the tube comprises a vaporizing portion and a condensing portion.
 10. The method as claimed in claim 8, wherein the driving member comprises four shrinkable chambers serially connected together.
 11. The method as claimed in claim 10, wherein the driving member drives the working fluid to flow from one chamber into a next adjacent chamber by shrinking of said one chamber.
 12. The method as claimed in claim 10, wherein each of said chambers is shrunk in light of an AC electrical signal imposed thereon.
 13. A heat dissipating device for dissipating heat from a heat-generating component, comprising: a hollow tube used to thermally contact said heat-generating component and gain heat from said heat-generating component at one portion thereof and dissipate said heat at another portion thereof; working fluid installed in said hollow tube and used to heat-exchange with said hollow tube at said one and another portions, and to flow within said hollow tube from said one portion to said another portion; and a driving member establishing another flow path from said another portion of said hollow tube to said one portion of said hollow tube outside said hollow tube, and comprising at least two fluid-containable, volume-variable chambers serially connected to each other so as to generate flow-diving force on said working fluid via volume variation of said at least two chambers.
 14. The heat dissipating device of claim 13, wherein said at least two chambers are made of piezoelectricity material and are electrifiable.
 15. The heat dissipating device of claim 13, wherein said volume variation of said at least two chambers are controlled by periodical alternating current (AC) signals respectively.
 16. The heat dissipating device of claim 13, wherein said one portion is a fluid-vaporizing portion and said another portion is a fluid-condensing portion, and phases of said working fluid within portions of said hollow tube other than said another portion are substantially different from phases of said working fluid within said another flow path established by said driving member. 